Monday, 8 October 2018

Wi-Fi Alliance has announced that the next generation WiFi technology, 802.11ax, will be known as Wi-Fi 6. This is to probably make it simpler, similar to mobile technology generations. Everyone knows 3G and 4G but how many people know UMTS or LTE. Similarly they are hoping that people will be aware of Wi-Fi 4, 5 & 6. They haven't bothered to name anything below Wi-Fi 4.

Looking at this picture from R&S above, you can see that according to Wi-Fi Alliance naming convention:

Some of you may be unaware that the US operator Verizon has formed 'Verizon 5G Technology Forum' (V5GTF) with the intention of developing the first set of standards that can also influence the direction of 3GPP standardization and also provide an early mover advantage to itself and its partners.

Verizon has posted its second round of work with its partners on a 5G specification. The first round was around the 5G radio specification; this time the work has been on the mechanics of connecting to the network. The operator has been working on the specification with Cisco Systems Inc., Ericsson AB, Intel Corp., LG Electronics Inc., Nokia Corp., Qualcomm Inc. and Samsung Corp. via the 5G Technology Forum (V5GTF) it formed late in 2015.Sanyogita Shamsunder, director of strategy at Verizon, says that the specification is "75% to 80% there" at least for a "fixed wireless use case." Verizon is aiming for a "friendly, pre-commercial launch" of a fixed wireless pilot in 2017, Koeppe notes.

Before we go further, lets see this excellent video by R&S wherein Andreas Roessler explains what Verizon is up to:

Verizon and SKT are both trying to be the 5G leaders and trying to roll out a pre-standard 5G whenever they can. In fact Qualcomm recently released a 28 GHz modem that will be used in separate pre-standard 5G cellular trials by Verizon and Korea Telecom

The Snapdragon X50 delivers 5 Gbits/second downlinks and multiple gigabit uplinks for mobile and fixed-wireless networks. It uses a separate LTE connection as an anchor for control signals while the 28 GHz link delivers the higher data rates over distances of tens to hundreds of meters.

The X50 uses eight 100 MHz channels, a 2x2 MIMO antenna array, adaptive beamforming techniques and 64 QAM to achieve a 90 dB link budget. It works in conjunction with Qualcomm’s SDR05x mmWave transceiver and PMX50 power management chip. So far, Qualcomm is not revealing more details of modem that will sample next year and be in production before June 2018.

Verizon and Korea Telecom will use the chips in separate trials starting late next year, anticipating commercial services in 2018. The new chips mark a departure from prototypes not intended as products that Qualcomm Research announced in June.

Korea Telecom plans a mobile 5G offering at the February 2018 Winter Olympics. Verizon plans to launch in 2018 a less ambitious fixed-wireless service in the U.S. based on a specification it released in July. KT and Verizon are among a quartet of carriers that formed a group in February to share results of early 5G trials.

For its part, the 3GPP standards group is also stepping up the pace of the 5G standards efforts it officially started earlier this year. It endorsed last month a proposal to consider moving the date for finishing Phase I, an initial version of 5G anchored to LTE, from June 2018 to as early as December 2017, according to a recent Qualcomm blog.

Coming back to Verizon's 5G standard, is it good enough and compatible with 3GPP standards? The answer right now seems to be NO.

The issue is that Verizon’s specs include a subcarrier spacing value of 75 kHz, whereas the 3GPP has laid out guidelines that subcarrier spacing must increase by 30 kHz at a time, according to research from Signals Research Group. This means that different networks can work in synergy if required without interfering with each other.Verizon’s 5G specs do stick to 3GPP requirements in that it includes MIMO and millimeter wave (mmWave). MmWave is a technology that both AT&T and Verizon are leading the way in – which could succeed in establishing spectrum which is licensed fairly traditionally as the core of the US’s high frequency build outs.A Verizon-fronted group recently rejected a proposal from AT&T to push the 3GPP into finalizing an initial 5G standard for late 2017, thus returning to the original proposed time of June 2018. Verizon was supported by Samsung, ZTE, Deutsche Telecom, France Telecom, TIM and others, which were concerned the split would defocus SA and New Radio efforts and even delay those standards being finalized.Verizon has been openly criticized in the industry, mostly by AT&T (unsurprisingly), as its hastiness may lead to fragmentation – yet it still looks likely to beat AT&T to be the first operator to deploy 5G, if only for fixed access.Verizon probably wants the industry to believe that it was prepared for eventualities such as this – prior to the study from Signal Research Group, the operator said its pre-standard implementation will be close enough to the standard that it could easily achieve full compatibility with simple alterations. However, Signals Research Group’s president Michael Thelander has been working with the 3GPP since the 5G standard was birthed, and he begs to differ.Thelander told FierceWireless, “I believe what Verizon is doing is not hardware-upgradeable to the real specification. It’s great to be trialing, even if you define your own spec, just to kind of get out there and play around with things. That’s great and wonderful and hats off to them. But when you oversell it and call it 5G and talk about commercial services, it’s not 5G. It’s really its own spec that has nothing to do with Release 16, which is still three years away. Just because you have something that operates in millimeter wave spectrum and uses Massive MIMO and OFDM, that doesn’t make it a 5G solution.”

Back in the 3G days, NTT Docomo was the leader in standards and it didn't have enough patience to wait for 3GPP standards to complete. As a result it released its first 3G network called FOMA (Freedom of Mobile Access) based on pre-standard version of specs. This resulted in handset manufacturers having to tweak their software to cope with this version and it suffered from economy of scale. Early version of 3G phones were also not able to roam on the Docomo network. In a way, Verizon is going down the same path.

While there can be some good learning as a result of this pre-5G standard, it may be a good idea not to get too tied into it. A standard that is not compliant will not achieve the required economy of scale, either with handsets or with dongles and other hotspot devices.

Wednesday, 10 August 2016

Rohde & Schwarz has just published a new whitepaper on Narrowband Internet of Things (NB-IoT).

NB-IoT has been introduced as part of 3GPP Rel-13 where 3GPP has specified a new radio interface. NBIoT is optimized for machine type traffic and is kept as simple as possible in order to reduce device costs and to minimize battery consumption. In addition, it is also adapted to work in difficult radio conditions, which is a frequent operational area for certain machine type communication devices. Although NB-IoT is an independent radio interface, it is tightly connected with LTE, which also shows up in its integration in the current LTE specifications.

The paper contains the necessary technical details including the new channels, new frame and slot structure, new signalling messages including the system information messages, etc. It's a good read.

Thursday, 2 October 2014

I am sure many people would have heard of ET (Envelope Tracking) by now. Its a technology that can help reduce the power consumption by our mobile devices. Less power consumption means longer battery life, especially with all these new features coming in the LTE-A devices.

As the slide says, there are already 12 phones launched with this technology, the most high profile being iPhone 6/6 Plus. Here is a brilliant presentation from Nujira on this topic:

R&S (who were the sponsors) gave their introduction presentation quite well highlighting the need and approaches for the connected car. He also introduced the IEEE 802.11p to the group.

As per Wikipedia, "IEEE 802.11p is an approved amendment to the IEEE 802.11 standard to add wireless access in vehicular environments (WAVE), a vehicular communication system. It defines enhancements to 802.11 (the basis of products marketed as Wi-Fi) required to support Intelligent Transportation Systems (ITS) applications. This includes data exchange between high-speed vehicles and between the vehicles and the roadside infrastructure in the licensed ITS band of 5.9 GHz (5.85-5.925 GHz). IEEE 1609 is a higher layer standard based on the IEEE 802.11p."

Back in December, Dr. Paul Martin did an equally useful presentation in the Mobile Broadband SIG and his presentation is equally relevant here as he introduced the different terms live V2X, V2i, V2V, V2P, etc. I have embedded his presentation below:

Roger Lanctot from Strategy Analytics, gave us some interesting facts and figures. Being based in the US, he was able to give us the view of both US as well as Europe. According to him, “LTE is the greatest source of change in value proposition and user experience for the customer and car maker. Bluetooth, Wi-Fi, NFC and satellite connectivity are all playing a role, but LTE deployment is the biggest wave sweeping the connected car, creating opportunities for new technologies and applications.” His officially released presentation is embedded below (which is much smaller than his presentation on that day.

There were also interesting presentations that I have not embedded but other may find useful. One was from Mike Short, VP of Telefonica and the other was from Dr. Ireri Ibarra of MIRA.

The final presentation by Martin Green of Visteon highlighted some interesting discussions regarding handovers that may be required when the vehicle (and the passengers inside) is moving between different access networks. I for one believe that this will not be an issue as there may be ways to work the priorities of access networks out. Anyway, his presentation included some useful nuggets and its embedded below:

Monday, 24 June 2013

So it looks like in the latest 3GPP RAN meeting finally more than 2 carriers have been proposed for Carrier Aggregation. The TDoclist has a few items on 3 carriers for CA. In some cases its been specified that there is 1 uplink component carrier (1UL CC) but in other cases its not specified and I have not looked into details. Its good to finally see more than 2 carriers being discussed.

Now there is a possibility that we may have 2 contiguous bands and 1 band from an Inter-band so the naming would be accordingly. There are also going to be new carrier types (NCT), Band 29 for example. See details here.

Finally, If you want to learn more about Carrier Aggregation (CA) or other LTE-Advanced features, my article from last year, here, would be useful.

Thursday, 9 May 2013

Based on the success of the recent posts on eMBMS, here and here, this final post on this topic is a look at physical layer perspective from Test and Measurement point of view. Slides kindly provided by R&S

Sunday, 12 August 2012

Some months back R&S held a technical forum where there were many interesting talks and presentations. They have now uploaded video of all these presentations that can be viewed on their website (no embedding allowed).

The 3GPP TS 36.211 LTE standard defines antenna ports for the downlink. An antenna port is generally used as a generic term for signal transmission under identical channel conditions. For each LTE operating mode in the downlink direction for which an independent channel is assumed (e.g. SISO vs. MIMO), a separate logical antenna port is defined. LTE symbols that are transmitted via identical antenna ports are subject to the same channel conditions. In order to determine the characteristic channel for an antenna port, a UE must carry out a separate channel estimation for each antenna port. Separate reference signals (pilot signals) that are suitable for estimating the respective channel are defined in the LTE standard for each antenna port.

Here is my table that I have adapted from the whitepaper and expanded.

The way in which these logical antenna ports are assigned to the physical transmit antennas of a base station is up to the base station, and can vary between base stations of the same type (because of different operating conditions) and also between base stations from different manufacturers. The base station does not explicitly notify the UE of the mapping that has been carried out, rather the UE must take this into account automatically during demodulation (FIG 2).

If there is another way to show this physical mappings, please feel free to let me know.

Thursday, 2 July 2009

Free online LTE Tutorial is available at IEEE Communications Society Website, courtesy of Rohde & Schwarz. You can view the tutorial here.

Not long back, I saw R&S demo of CMW-500 with the LG UE at the LTE World Summit. R&S has also verified ETSI 3GPP LTE TTCN-3 test cases with Qasara and has shown successful interoperability testing between Qasara’s Virtual UE and Rohde & Schwarz's 3GPP LTE Virtual Tester.

There is also a LTE TDD Technology Overview available to download from their website here.

Sunday, 18 May 2008

In the past year or so there has been lot of talks about the next generation wireless technology and the significance toward adopting these technologies. One of such technology which is very much a popular discussion these days is LTE. Over the last one year LTE air interface and its architecture has become clearer. Significant developments have been made in finalising the LTE architecture and OFDMA and SC-FDMA as radio access technology. LTE as a technology has a come long way in terms of finalising the air interface and other standards. 3GPP1 and 3GPP2 is working hard to get the latest specification out so that telecomms companies start drafting their plans in order to implement the technology.

Giants like Nokia, NTT DoCOMO, Ericsson, Vodafone and others have already started their research and development on LTE thus giving enough indication that LTE is going to be the technology adopted by most as a next generation wireless technology.

Long-term evolution (LTE) promises to make everything from mobile-video sharing to music downloads speedier, but it may not show a visible boost in sales for the network equipment industry any time soon, as the first networks are not expected for two years and many operators will wait longer until the technology matures.

Verizon Wireless, the number-two US mobile service, has decided to build out an LTE network, while China Mobile, the world's biggest mobile provider, said earlier this year it would test LTE.Alcatel-Lucent and Japan's NEC signed a joint-venture deal to pool their development and marketing of the technology. Even Qualcomm has promised chips for LTE, a competitor to its own Ultra Mobile Broadband technology.

Ericsson recently unveiled a glimpse of what the future of mobile Internet will bring, announcing its new M700 mobile platform, capable of LTE (Long Term Evolution) data transfer speeds. Ericsson says this is "the world's first commercially available LTE-capable platform", and we have no choice than to believe it, especially since the Swedish company sustains the platform will bring data transfer speeds of up to 50Mbps (when uploading) and up to 100Mbps (when downloading). Sure, these speeds are not comparable with the ones achieved by NTT DoCoMo's Super 3G network (250Mbps), but they are obviously better than what the current 3G networks can offer. Moreover, these new speeds can surpass, in some cases, the data rates achieved by fixed lines, allowing the development of real-time mobile services, including video streaming and on-line gaming.

Nokia Siemens has already achieved speeds up to 173 Mbps with LTE in a trial of the LTE wireless data network. The field trial was conducted in an urban environment and was meant to test the performance of LTE in "real" environments. This is in contrast to a demonstration of the technology a year ago that achieved speeds up to 160 Mbps.

LTE technology is competing with WiMAX to deliver high speed mobile networks, and both have high profile supporters worldwide. The LTE project was designed to evolve the current 3G technology used today, and Erissson’s prototype together with the Nokia Siemens test shows clearly which camp the companies are in.

There are others who like Ericsson putting a lot of efforts in LTE and thus making it clearer that they prefer LTE as compared to WiMax.

During its first quarter conference call with investors, Alltel announced that it was committed to evolving its network to LTE over the next five years. The move makes Alltel the second biggest CDMA carrier in the U.S., after Verizon Wireless, to commit to the LTE standard, even though LTE was originally on the GSM evolution path. "We do currently plan to move towards LTE in the three-to-five year timeframe vs. WiMAX, but we're still early in that," President and CEO Scott Ford said during the call.

Huawei Technologies ("Huawei"), a leader in providing next generation telecommunications network solutions for operators around the world, has already announced that it has joined the Long Term Evolution / System Architecture Evolution (LTE / SAE) Trial Initiative ( LSTI ) and will hold the infrastructure vendor seat of the 2008 LTE/SAE Trial Initiative Steering Board.The LTE/SAE Trial Initiative brings together major telecom vendors and operators, committed to driving the development of next-generation, high-performance, mobile broadband networks and 3rd Generation Partnership Project (3GPP) LTE and SAE technologies. Huawei's active in LSTI reflects commitment to contributing significantly to the development of HSPA, HSPA+ and LTE technologies, as a leading global telecommunication solutions supplier.

Looking at the trends and developments in LTE, vendors has already started lashing out onLTE licensing.

Rohde and Schwarz is also not lagging behind in it’s efforts to make sure that its system simulators are available for the vendors when they are ready to test their first LTE device. By including the latest revisions of the 3GPP LTE standard in the firmware for its signal generators, Rohde and Schwarz is already offering highly flexible testing for LTE equipment. Rohde and Schwarz has added channel coding and MIMO precoding for up to four transmit antennas to its industry-leading signal generators for LTE (uplink and downlink) Whether mobile equipment manufacturers are looking for an all-in-one solution for 2x2 MIMO signals and real-time fading or simply need standard-compliant RF or baseband signals, Rohde and Schwarz offers the answer.